Merge pull request #8 from JuliaWeb/mime_from_contenttype

README.md

@@ -5,12 +5,15 @@ A small package to transform between file extensions and MIME types, with bonus
 ```julia
 julia> using MIMEs
 
+### For filename extensions:
 julia> m = mime_from_extension(".json")
 MIME type application/json
 
 julia> extension_from_mime(m)
 ".json"
 
+
+### For web servers:
 julia> compressible_from_mime(m) # whether content of this MIME can/should be gzipped
 true
 
@@ -19,6 +22,9 @@ julia> charset_from_mime(m)
 
 julia> contenttype_from_mime(m) # the Content-Type HTTP header
 "application/json; charset=utf-8"
+
+julia> mime_from_contenttype("application/json; charset=utf-8")
+MIME type application/json
 ```
 
 # Implementation

src/MIMEs.jl

@@ -1,6 +1,6 @@
 module MIMEs
 
-export mime_from_extension, mime_from_path, extension_from_mime, charset_from_mime, compressible_from_mime, contenttype_from_mime
+export mime_from_extension, mime_from_path, extension_from_mime, charset_from_mime, compressible_from_mime, contenttype_from_mime, mime_from_contenttype
 
 const _mimedb, _ext2mime, _mime2ext = include(joinpath(@__DIR__, "..", "mimedb", "mimedb.jlon"))
 
@@ -147,11 +147,35 @@ contenttype_from_mime(mime_from_extension(".png", MIME"application/octet-stream"
 ```
 
 # See also:
-[`charset_from_mime`](@ref)
+[`charset_from_mime`](@ref), [`mime_from_contenttype`](@ref)
 """
 contenttype_from_mime(mime::MIME) = let c = charset_from_mime(mime)
     c === nothing ? string(mime) : "$(string(mime)); charset=$(lowercase(c))"
 end
 
 
+"""
+```julia
+mime_from_contenttype(content_type::String[, default::T=nothing])::Union{MIME,T}
+```
+
+Extract a MIME from a Content-Type header value. If the input is empty, `default` is returned.
+
+# Examples:
+```julia
+mime_from_contenttype("application/json; charset=utf-8") == MIME"application/json"()
+mime_from_contenttype("application/x-bogus") == MIME"application/x-bogus"()
+mime_from_contenttype("") == nothing
+mime_from_contenttype("", MIME"application/octet-stream"()) == MIME"application/octet-stream"()
+```
+
+# See also:
+[`contenttype_from_mime`](@ref)
+"""
+function mime_from_contenttype(content_type::String, default=nothing)
+    result = strip(split(content_type, ';')[1])
+    isempty(result) ? default : MIME(result)
+end
+
+
 end

test/runtests.jl

@@ -38,6 +38,12 @@ sub(s) = SubString(s, 1)
 @test contenttype_from_mime(MIME"application/x-bogus"()) == "application/x-bogus"
 @test contenttype_from_mime(mime_from_extension(".png", MIME"application/octet-stream"())) == "image/png"
 
+
+@test mime_from_contenttype("application/json; charset=utf-8") == MIME"application/json"()
+@test mime_from_contenttype("application/x-bogus") == MIME"application/x-bogus"()
+@test mime_from_contenttype("") == nothing
+@test mime_from_contenttype("", MIME"application/octet-stream"()) == MIME"application/octet-stream"()
+
 # from https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
 const mdn = Dict(
     ".bin" => "application/octet-stream",